【正文】 ersion efficiencies are of the same order of magnitude of roughly 10–15%. In the case of many developing countries current patterns of energy production and use (. the baseline scenario) are not fossil fuels, but some form of bioenergy, albeit mostly produced and utilized in an inefficient and environmentally harmful manner. Energy efficiency improvements often represent a straightforward option for emission reductions, as the existing fuel cycles do not have to be changed and thus nonfinancial barriers to adoption are more likely to be rather low. On the other hand, investment in new equipment and upfront financing are usually not readily available. . THE SCOPE FOR EMISSION REDUCTION THROUGH BIOENERGY The assessment of potential carbon emission credits generated by a bioenergy project requires the parison of greenhouse gas emissions over the entire life cycle of the energy chain, including the production of raw materials and their conversion to useful energy. Bioenergy projects may mitigate GHG emissions in two ways: (1) from the sequestration generated if carbon stocks in the terrestrial biosphere can be increased. (2) by lower emissions associated with the production and use of bioenergy, as pared with that of the fossilbased energy. In terms of reducing greenhouse gas emissions, results vary according to the emissions at each step in the production chain. Sequestration of CO2 of 60 to 87 GtC in carbon sinks over a 50 year time span ( to GtC per year) could be achieved through landuse related activities, which is to 7–15% of average fossil fuel emissions estimated for the 2020 to 2050 period (IPCC 2020a,b). For the Brazilian sugarcane agroindustry it was estimated, that after including all emissions in the production process, it is through the substitution of gasoline by ethanol (～65%) and fuel by bagasse (～ 35%), that Carbon emissions are reduced by Mt C/yr (Hall et al. 2020, p. 47). Generally, CO2 emissions in the conversion of biofuels to electricity and heat are lower by at least one order of magnitude than in reference cases using fossil fuels and constitute “an important option to reduce emissions of CO2” (Groscurth et al. 2020, p. 1092). “The potential global contribution of bioenergy has been estimated to be between 95 and 280 EJ in the year 2050 (Hall and Scrase 1998), leading to a potential reduction/avoidance in emissions of between and GtC per year, or between roughly 5% and 25% of projected fossil fuel emissions for the year 2050 (IPCC 2020b).” (IEA Bioenergy T38, 2020) Studies in Asia for example have shown that CO2 emissions could be significantly reduced if more efficient cooking stoves would be introduced, or biofuels (. rice husks) would be used more efficiently, in power and electricity production. Kaltschmitt (2020) identifies large potentials for efficiency improvements in current bioenergy applications, on both industrial and household scales (see also Figure 1). At the same time, less need for fuel wood bears obvious potential for improving the livelihood of people. . HOW IS BIOENERGY CONSIDERED IN THE KYOTO PROTOCOL The Kyoto Protocol defines limitations on emissions of CO2, N2O, CH4 and three industrial gases from the following sectors of Annex I countries: ? Energy ? Waste ? Industrial Processes ? Agriculture Bioenergy activities in Annex I countries have three distinct effects on the carbon balance: ? They substitute for fossil fuels (including the fossil fuels that are required to mine, transport, refine fossil fuels) ? They can change the carbon balance of the terrestrial biosphere ? They may require the use of fossil fuels in their production, processing, transportation, and enduse conversion The first effect is implicitly considered in the Kyoto Protocol, because any reduction in the use of fossil fuels in the country of interest can be seen in the overall GHG emissions of the energy sector. The emissions from auxiliary fossilfuel use from producing fossil fuels will only be seen if they would have occurred in the same country. The third effect will also be covered by the Kyoto emissions inventory, to the extent that these emissions occur in the country of interest. The second effect can be achieved through either bioenergy efficiency improvements (. biofuel saving) or through switching from non renewable biomass to renewable biomass resources (. substitution. Both options will be discussed in more detail in the following section, as a proper understanding of these options is crucial for the following evaluation of their eligibility according to the existing modalities and procedures of the KP. . FUEL SAVING – IMPROVING ENERGY EFFICIENCY Different categories of emission reduction through efficiency improvements can be distinguished: 1. CO2 emission reductions related to energy inputs into the fuel cycle, mostly during the production and conversion stages. These are eligible to the extent that the baseline is bustion of fossil fuels. 2. NonCO2 emission reductions related to end use efficiency (and possibly, conversion). Increasing the efficiency of (.) fuel